Single set production-injection packers operated by hydraulic fluid pressure are well known in the art, with an exemplary packer described in U.S. Pat. No. 4,349,204, hereby incorporated by reference. In many downhole environments, such packers and the actuator or setting mechanisms may be reliably utilized for conventional hydrocarbon recovery operations.
In other situations, such as recovery operations in California involving heavy crude, the high viscosity crude is recovered by injecting high-temperature/high-pressure steam with additives into the well. The packer enables steam to be injected through the packer and into the formation while sealing the annulus between the tubing and casing. The packer then holds pressure within the formation as the steam migrates into the formation to enhance the recovery operation.
When prior art packers and setting assemblies are utilized in such environments, the fluid pressure in the packer rises with the injection of steam and the resultant increase in packer temperature. During the soak operation, the formation absorbs steam and the temperature decreases in the area adjacent the packer, causing a corresponding decrease in the packer fluid pressure. When utilizing a hydraulic packer in such situations, difficulties are thus encountered in effectively maintaining sealed engagement with the tubing and the casing and, accordingly, either a mechanical packer is utilized or the hydraulic packer is reset at various times during the hydrocarbon recovery operation by altering packer fluid pressure from the surface. A mechanical packer may, however, not be preferred in such situations, and the latter technique involves additional time and labor.